Progress in Electronic Frequency Control of Superconducting Helix Resonators

This paper describes a series of improvements for the frequency control system of superconducting helix accelerating structures. The improvements are such, that costs and reliability of the control equipment to suppress the mechanically induced eigenfrequency vibration become competitive with those of mechanically more stable structures like the split-ring. In this manner the main limitation of the practical use of the helix are overcome. Consequently, the merits of the helix, i.e. its simple fabrication, can be fully exploited and the helix becomes a serious candidate for heavy ion and proton accelerators.